#include <cmath>#include <cstdio>#include <vector>#include <iostream>#include <set>#include <algorithm>using namespace std;int main() { /* Enter your code here. Read input from STDIN. Print output to STDOUT */ int q = 0, x = 0, y = 0; cin >> q ; set<int> s ; set<int> it ; for(int i = 0 ; i < q ; i++) { cin >> x >> y ; switch (x) { case 1 : s.insert(y); break; case 2 : s.erase(y); break; case 3 : if(s.find(y) != s.end()) cout << "Yes\n" ; else cout << "No\n" ; break; } } return 0;}